1. Field of the Invention
This invention relates to an improved coating composition which imparts superior blood-barrier properties, as well as desirable water-barrier, antistatic and antislip characteristics to a fibrous polyolefin sheet coated therewith. In particular, the invention concerns such a coating composition which contains powdered polytetrafluoroethylene, methods for preparing the coating composition and fibrous polyolefin sheets coated with the coating composition.
2. Description of the Prior Art
U.S. Pat. No. 4,082,887 discloses a coating composition which imparts desirably high water-barrier, antislip and antistatic properties to a fibrous polyolefin sheet coated therewith. Such coated sheets have been used for gowns and drapes in hospital operating rooms. The coating composition of U.S. Pat. No. 4,082,887 is in the form of an aqueous dispersion that contains 10-40% by weight solids. The solids consist essentially of effective amounts of (a) a water-insoluble wax, (b) an antistat, (c) a nonionic surfactant and (d) a water-insoluble binder resin. Example 5 of the patent discloses such a composition which also includes an anionic aqueous dispersion of a fluoropolymer useful as an alcohol repellent. This composition, when coated onto a nonwoven fibrous polyolefin sheet and then dried, is stated to provide the coated sheet with high water-barrier, antistat, antislip and alcohol-barrier properties. However, applicant has found that improvements are needed in the blood-barrier properties of such coated sheets.